I just did the NHS heart age calculator -
https://www.nhs.uk/health-assessment-tools/calculate-your-heart-age
and was asked for my sex / sex at birth - and to ask my GP if I had further questions about this.
i think that is an acceptable compromise - everyone knows what sex they are, the birth qualifier isn’t necessary but doesn’t create further confusion, and anyone who doesn’t know what sex to put seeks further advice.
No mention of gender. Clear writing.
I am interested in what others think - is this ok?